Conventionally, an electric motor or air motor is used as a starter for the emergency engine generator. For example, the electric motor is used for the starter of the emergency generator equipped with a liquid-fuel engine because a gas-fuel supply from town gas facilities can be disconnected in case of disasters such as earthquakes. The air motor, on the other hand, is used for the starter of the emergency generator with a gas turbine engine which drives using energy obtained by combusting gaseous fuel because an internal spark in the electric motor can ignite leaked gas.
Accordingly, as described in JP 6-173715 A, the conventional air motor starter is designed so that high pressure air is accumulated in air supply tanks to supply pressurized air for the air motor, which needs a large scale compressor for generating the high pressure air.
Using the electric motor as the starter needs the power supply batteries for driving the motor to be recharged up to a certain voltage after the completion of the driving of the engine. Typically, the recharge takes considerable time. This means that, if another outage would occur during the recharge, it may be impossible to re-energize the engine. Also, the discharged batteries should promptly be replenished with electricity, which needs that the batteries are always electrically connected to a battery charger. Further, weakness of battery should always be detected. Furthermore, the disposal of exhausted batteries results in environmental pollution.
Using air motor needs an air compressor and a high-pressure reservoir, which requires a large space for their installation and their installation works. Also, noise and vibration reduction facilities are needed to reduce noises and vibrations which occur during operations of the air compressor. Further, a drain chamber is needed for removing lubricant oil from the drive source of the air compressor and the compressed air generated by the air compressor, which increases the installation cost and causes additional costs for maintenance of the drain chamber and for disposal of the lubricant collected at the drain chamber. Furthermore, a larger high-pressure reservoir is needed to drive the air motor for energizing the engine frequently. However, a considerable time is required to fill the tank with the pressurized air.
Accordingly, the present invention is to provide an emergency engine generator which uses fire-extinguishing gas from fire-extinguishing equipment as driving medium for driving the engine in a reliable manner and needs minimum space and costs such as facility and running costs.
To this purpose, an embodiment of an engine generator according to the invention, which is attached to a fire extinguishing facility designed to eject unburnable gas supplied from gas containers, comprises an air motor for energizing an engine; and a start-up valve unit which is designed to drive in response to a start-up instruction signal, control a pressure of the unburnable gas from the gas container and supply the pressure controlled unburnable gas to the air motor.
According to the engine generator, in case of outrage the air motor is driven using the unburnable gas from the gas container. Then, the engine is energized by the air motor. Accordingly, no conventional large air compressor or the reservoir for accommodating the compressed air is needed. This results in that an installation space and a manufacturing cost of the engine generator are considerably reduced. Also, a running cost is also reduced considerably because the maintenance needs only replacing the used gas containers. Further, the fire extinguishing gas for use in the fire extinguishing facility which is required to be installed in the buildings and business facilities is used for driving the air motor to energize the engine, which does not need additional gas containers exclusively for the driving gas source of the air motor. This considerably simplifies the overall structure including the fire extinguishing facility. Also, the fire extinguishing facility can be administered in association with the overall maintenance of the engine generator. Further, because the valve unit controls the pressure of the unburnable gas from the gas container to a certain pressure suitable for the driving of the air motor, which ensures that the air motor drives in a reliable manner to energize the engine.
Preferably, nitrogen gas is used for the unburnable gas because the nitrogen gas is unlikely to ignite at high pressures and therefore it is preferably used as a driving fluid of the air motor for energizing the gas-fuel engine. Also, the nitrogen gas does not result in generation of air pollution or greenhouse effect.
Preferably, the start-up valve unit reduces the pressure of the unburnable gas from the gas container. This ensures that the pressure of the unburnable gas is reduced to a predetermined pressure suitable for driving the air motor even if the pressure of the unburnable gas in the gas container is inappropriate for driving the air motor or varies with respect to each container. This in turn allows using commercially available gas containers containing the unburnable gas at different pressures.
Preferably, the engine generator comprises a fire extinguishing gas passage for supplying the unburnable gas from the gas container, and a gas supply passage which is branched from the fire extinguishing gas passage for supplying the unburnable gas to the air motor. This allows that the unburnable gas is supplied to the air motor as driving gas, with a simple arrangement of providing the branched passage.
Preferably, the engine generator comprises a plurality of spare container units, each unit having a plurality of spare gas containers for containing unburnable gas to be used for a one-time driving of the engine. This allows that, when it is impossible to use the unburnable gas from the gas containers in the fire extinguishing facility for some reason, the engine is driven by using the unburnable gas of the spare containers. Also, the plurality of spare container units allow the engine to be driven a plurality of times. Further, small-sized commercially available economical gas containers can be used for the spare containers to construct the spare gas unit with a certain amount of gas needed for the one-time driving of the engine.
The engine generator according to another embodiment of the invention comprises an engine, an electric generator to be driven by the engine, an air motor for driving the engine, a gas container for containing unburnable gas and a valve unit for controlling a pressure of the unburnable gas from the gas container in response to a start-up instruction and supplying the pressure controlled unburnable gas to the air motor.
According to the arrangement, the air motor is driven by the unburnable gas from the gas container. This allows the engine to be driven at electric outage and no conventional large-scale compressor or reservoir for accommodating the compressed air is needed, which considerably reduces the installation space or manufacturing cost. Further, the maintenance needs only replacement of the used gas containers, which also reduces running cost considerably. Furthermore, the valve unit controls the pressure of the unburnable gas from the gas container to a certain pressure suitable for driving of the air motor, which ensures a reliable driving of the air motor to energize the engine.
Preferably, the engine generator comprises a plurality of container units, each unit having a plurality of gas containers for containing unburnable gas to be used for a one-time driving of the engine. This arrangement allows the small-sized commercially available gas containers are used to construct the container unit with a certain amount of gas necessary for the one-time driving of the engine. Also, the plurality of container units, each unit being used for one-time driving of the engine, allows the engine to be driven a plurality of times.
According to the engine generator of the invention, the engine can be energized even at electric outrage. Also, no conventional large air compressor or the air reservoir for accommodating the compressed air is needed. This results in that an installation space and a manufacturing cost of the engine generator are considerably reduced. Also, a running cost is also reduced considerably. Further, the valve unit controls the pressure of the unburnable gas from the gas container to a certain pressure suitable for driving of the air motor, which ensures a reliable driving of the air motor to energize the engine.